Revisiting Black Mesa

It's Black Mesa, but not quite as you knew it. A tight edit of the familiar, the sublime and those ridiculous scientist ties, this free re-imagining of Half-Life is packed with new dialogue, subtly altered levels and all the fiery and physical powers that the Source engine can imbue.

The Black Mesa project was finally released for free last Friday, and it's more than a dodgy cover version. First and foremost, of course, it's a fantastic remake: every stupendous moment of Valve's original masterpiece has been replicated in glorious modern technicolor.

After that unfortunate resonance cascade, for example, you'll see Source powered renditions of the Anomalous Materials Greatest Hits that amazed you the first time round. The security guard performing CPR on the scientist, the collapsing computer units, the lift that not only took you downwards but (gasp!) rotated at the same time.

At the edges of both the iconic and every-day moments that Half-Life permanently embossed onto your memory, however, are the grey areas that the Black Mesa team have filled in with some of their own colour. They've toyed with level lay-outs, the order you pick up weapons, which enemies crop up where and even where you first discover that fateful crowbar. As a result, the game can and will surprise, making the biggest impact on the more elderly and forgetful players who first piloted Freeman towards Xen in the days of yore. It's like returning to school for a ten year reunion, only to have your mind gently boggled by the fact that they've built a new science department and that the teachers, somehow, now appear to be human beings.

As with the original game the best character in the game is Black Mesa itself - the incalculably vast facility that acted as something of a fore-runner to Portal 2's treatment of Aperture Science.

Much of this comes, clearly, with the relentless march of progress. What was once a large room frequented by a couple of tables and some antsy headcrabs, for example, can now suddenly be reimagined as a workplace cafeteria. What was once a boring old control room for an industrial lift, too, can now be littered with impressively decorated screens and a mug with a picture of the Chuckle Brothers on it. This all said, Source doesn't just mean a face-lift for the facility - the way the whole secret scientific enterprise works must be subtly upgraded too.

The advent of physics, for example, means that the hanging crates you leap between gently sway, while objects are picked up, thrown and merrily ricocheted around military camps after explosions. In Valve's later Half-Life adventures zombies became rather combustible - so now, an early threat to Black Mesa's health and safety record are the flares that can be tossed at headcrabbed scientists with flaming results.

Add to all this the wider levels, fewer loads, smashable glass, cinematically crumbling bridges, rooms of sleeping Houndeyes and physically weighted Bullsquid flob then you've genuinely got a Black Mesa experience that's as revamped as it is authentic. This is a far, far cry from the desultory copy and paste job that was the official Half-Life: Source.

The fact that the appearances of your fellow scientists (if not, perhaps, their animation) is suddenly on a par with Half-Life 2 is also wonderful - although it does make you feel bad when cutting off their sentences with a bullet. NPCs can be encouraged to follow you with a tap of the space bar, just as they were once wont to do, although now you can form up something of a posse as you stalk the halls of the facility.

It makes you feel a little guilty when run-jumping into a lift shaft and leaving them to their fate - but the raft of new dialogue lines, the more decorated laboratories and the fact that your charges don't all share the same faces invoke a much deeper spirit of scientific camaraderie. Hell, they've even hired a few women - meaning that Black Mesa has finally become the equal opportunities employer it so proudly boasts in the opening tram-ride. The appearance of younger versions of Kleiner and Eli Vance in the opening levels, meanwhile, are neat tie-ins to Gordon's later adventures in space and mime.

There are a few issues, and a few stutters and long load-times, but Black Mesa remains an astounding achievement

As with the original game the best character in the game is Black Mesa itself - the incalculably vast facility that acted as something of a fore-runner to Portal 2's treatment of Aperture Science. Its treatment in the Source Engine brings in an unparalleled sense of scale as you journey through its depths, up to the surface for a brief glimpse of blue sky and then back into its network of inky black shafts, giant fans and seemingly endless rickety service ladders. Strange to say, but the glowing green sheen of radioactive liquid that the Black Mesa team have somehow found in their collective colour palette is one of the most striking things to decorate my monitor in years.

Tinkering with a classic is always a dangerous pursuit, but those who first paid dotage to the original Half-Life will only have minor quibbles in Black Mesa. The iron sight view on the magnum seems a little redundant compared to the old zoom-in, the Bullsquid is too easy to kill and the gut-wrenching terror of the Ichthyosaur seems to have been dialled back a little.

Likewise, the AI of the military doesn't quite match up to your memories of Surface Tension cat and mouse either - but, then again, the Combine grunt AI in Half-Life 2 didn't either. The new 'sound-a-like' recordings are perfectly done, meanwhile, but I'd be lying if I said I didn't miss the strange reedy fuzz that used to sit behind NPC voices. As a final note Black Mesa currently ends with the leap to Xen, so I can't yet tell whether the giant swinging testicle of the Gonarch is even more terrifying when imbued with real physical properties.

So yes there are a few issues, and a few stutters and long load-times, but Black Mesa remains an astounding achievement. It's a breathless mix of the old and the reimagined - and you can feel a shared passion for the original game running behind every grimy wall. The cohesion, organisation and sheer gumption that must have been shown internally by the Black Mesa team is quite staggering - especially for a mod project that's been around for eight long years.

It genuinely feels like something of an insult to its creators that we can all sample the fruits of their extensive labour for free. One can only hope that Uncle Valve might find a way to reward them for their startling act of devotion.